Gage-snap roll thread



'March 12, 1963 c. A. GRANZOW GAGE-SNAP ROLL THREAD Filed Oct. 17. 1960 IN V EN TOR.

ATTORNEYS United States Patent Ohhce 3,980,666 Patented Mar. 12, 1963 3,030,660 GAGE-SNAP ROLL THREAD Carl A. Grauzow, Dayton, Ohio, assignor to the United States of America as represented by the Secretary of the Air Force Filed Oct. 17, 1960, Ser. No. 63,229 2 Claims. (Cl. 33-199} (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to me of any royalty thereon.

This invention relates to measuring instruments and more particularly to thread gages of the go or no go types known more commonly as Snap Roll Thread Gages.

Conventional snap roll thread gages comprise a heavy precision-made, U-shaped body and two pairs of precision thread gage rolls are eccentrically mounted, one pair at opposite sides of the entrance of the U-shaped opening having a thread periphery corresponding to the threads of the bolt, stud, or threaded rods, and are spaced apart a distance which will just pass the threaded piece to be gaged therebetween with the maximum prescribed predetermined, oversized clearance. The other or second pair of thread gage rolls are likewise eccentrically mounted at opposite sides of the U-shaped opening and inwardly of the first set of threaded rolls, however, this set is spaced closer together than the first pair, at a separated distance which is equal to the maximum predetermined undersize allowance provided for the gaged threaded element. Thus, if the threaded elements will not pass the outside rolls it is to be rejected as beyond the oversize limit while if it passes the outside rolls but does not pass the inside rolls it is within the tolerance allowed, and if it passes the inside rolls it is rejectable as being too much undersize.

These gage devices are expensive and must be stocked for a considerable number of different threads and sizes.

An object of this invention is to reduce stock inventories of these gages and the aggregate bulk of the gage frames by using one gage frame for a plurality of thread sizes. For instance, a No. 6 frame can be used by utilizing my invention covering /5", A" and 5 size gages, where heretofore a complete gage and frame was required for each of the above sizes. This provides an important reduction to at least one-fourth the present requirements.

Another object of the invention is the provision of a gage which will be cheaper on new procurement as modified according to the invention.

A further object of the invention is the provision of a gage in which replacements of the gage elements in their assembled relation can be made without the necessity of the replacement of the frame.

A further object is the provision of a snap roll thread gage in which three to four sizes of gages can be adapted to one of approximately 21 sizes of frames thereby simplifying procurement and storage, and a great savings to the purchaser.

A further object is the provision of a single U-shaped frame precision machine on one side to receive a plurality of different, precision machined, U-shaped fiat plates, each having eccentric mounted go and no go pairs of thread gage rolls thereon which are disposed in the U-shaped opening of the frame and means for securely but removably mounting the plate on the U-shaped frame whereby the U-shaped frame provides the necessary support and strength for holding the plate and its gage rolls in precise desired spaced relationship against movement and spreading, and protects the rolls from damage during handling and gaging operations.

Other objects and advantages of the invention will become readily apparent from the following description and accompanying drawings in which like reference characters refer to like part-s in the several figures.

In the drawings:

FIG. 1 is a plan view of a snap roll gage incorporating the invention;

FIG. 2 is a side elevation of the gage shown in FIG. 1;

FIG. 3 is an end elevation looking toward the entrance end;

FIG. 4 is a longitudinal sectional view taken about on line 4-4 of FIG. 1, looking in the direction of the arrows; and

FIG. 5 is a sectional view taken about on line 5-5 of FIG. 1.

In the accompanying drawings the reference numeral 1 denotes a heavy rigid body or frame of any suitable construction, that illustrated being of generally U-shaped form having a strengthening flange and web portion 3 in the handle portion 2 with the usual eye 4 at its rear or handle end portion 2. The body or frame 1 is provided with a wide U-shaped opening 5 or entrance and throat to accommodate the pairs of gaging rolls 66 and '7'7.

The body 1 has one side surface 8 thereof precision machined flat to receive the removable, adjustable gaging unit 9 thereon, having a rigid plate 10, a fiat surface disposed in tight engagement with the machined surface 8 of the body 1.

This plate 16 substantially conforms to the peripheral contour of the body portion adjacent to and surrounding the U-shaped opening 5 and has a narrower U-shaped opening 11 which is wide enough to pass the largest diameter threaded stock that is to be gaged by the device. The U-shaped opening 5 in the body 1 is considerably wider and longer than the U-shaped opening 11 in the plate In as seen in the drawings, particularly FIGS. 1 and 4 and the supporting gage plate 10 therefore projects materially beyond the wider opening 5 on all three sides thereof.

The gage plate 10 is securely, but removably, fastened to the machined surface 8 of the body by four (or more) screw fasteners 12, the overhanging portion 10 of the plate carrying the two pairs or sets of the thread gaging rolls previously indicated generally at 6-6, and 77, the periphery of the rolls projecting beyond the sides of the U-shaped opening 11 while the two gage rolls are located and protected within the larger U-shaped opening 5 and do not extend axially beyond the planes of the top and bottom surfaces of the body 1 and are therefore fully protected by the body and their removable gage plate 10.

The gage rolls 66 and 7-'7 and their mounting on the plate 1t} are somewhat conventional, being mounted to provide a limited adjustment for each pair toward or away from each other. The rolls are of course threaded as shown with threads complementary to the threads of the stock to be gaged thereby.

As seen in FIG. 5 one form of structure for the rolls and the mounting is illustrated in which a roll 6 is in the form of a threaded sleeve 13 having a central cylindrical bearing surface and counterbored at its outer end to receive the head 15 of a cap screw 16. The adjustment means comprises an eccentric sleeve 17 having an outer bearing surface for the gaging roll 13 and an inner eccentric bore receiving the body or shank of the cap screw 16. These sleeves 17 can thus be rotatably adjusted to provide a slight adjustment in the space between the peripheries of the gage rolls 6--6 and 7-7 for finer or courser clearance tolerances between the rolls.

counterbored. portion of the rolls 13 to, provide for freev rotation thereof on thesleeves.

The body l as indicated is used-with a plurality of different size gage plates, by simply, selecting the desired gage plate and securing it to the body by the four screws 12. Thus, the same body 1 can be employed for gaging a plurality of difierent diameters or sizethreaded stocks, by, clamping thegage plates and the-threaded gage rolls are amply protected by the body against accidental damage during-use or mishandling, dropping,- etc.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is set forth in the following claims:

1. A go, nojgo thread gage comprising a U-shaped rigid supporting body having a wide U-shaped opening in one end thereof, a rigidflat gage plate removably mounted on one side of said body in overlying relationto theopposite edges of thetU-shaped opening in the body,

similarly oriented relation to the U-shapednopening in the body, a first pair of go threadgaging rolls mounted? on said plate at oppositesides of the entrance-,- end.of the1 U-shaped opening in said plate and confined wholly with-" in-the gwider- U-shaped openingin theibody, andi asecond pair of no go thread gaging rolls mounted on said .plate at-opposite sides of the U-shapedopening in the platebetween, thetfirstupair of gothread gage rolls and the 4, inner end of the U-shaped opening in the plate, and confined wholly within the wider U-shaped opening in the body.

2. A snap roll thread gage device comprising a heavy rigid supporting portable body of substantially U-shaped form having awide substantially U-shaped opening extending into one end thereof having at least one supportstock to be gaged therein, a first pair of threaded thread gaging rolls mountedon said plate adjacent each side of the entrance end of the U-s-haped'opening in the plate and projecting into the, U-shaped opening of the body and, spaced apartjust sufiiciently for passing a threaded stock of predetermined maximum limit thread diameter. therebetween, into the U,-shaped,openings,,a second pair of, thread gage rolls mounted on. said, plate atopposite sides. of the U-shaped openingtherein and inwardly of the first pair of rollsvforobstructing the passage therebetween offa threaded stock over/a predetermined minimum limit, thread diameterand passing therebetween a threaded stock having a thread diameter. less .than, said. predetermined,

minimum limit thread diameter.

RefereucesCited in the file of this patent FOREIGN PATENTS 873,750 Germany Apr. 16 1953' 

1. A "GO, NO GO" THREAD GAGE COMPRISING A U-SHAPED RIGID SUPPORTING BODY HAVING A WIDE U-SHAPED OPENING IN ONE END THEREOF, A RIGID FLAT GAGE PLATE REMOVABLY MOUNTED ON ONE SIDE OF SAID BODY IN OVERLYING RELATION TO THE OPPOSITE EDGES OF THE U-SHAPED OPENING IN THE BODY, MEANS REMOVABLY SECURING SAID PLATE RIGIDLY TO SAID BODY IN SAID OVERLYING RELATION, SAID PLATE HAVING A NARROWER AND SHORTER U-SHAPED OPENING THEREIN THAN THE U-SHAPED OPENING IN THE BODY EXTENDING INTO ONE END THEREOF IN SIMILARLY ORIENTED RELATION TO THE U-SHAPED OPENING IN THE BODY, A FIRST PAIR OF "GO" THREAD GAGING ROLLS MOUNTED ON SAID PLATE AT OPPOSITE SIDES OF THE ENTRANCE END OF THE U-SHAPED OPENING IN SAID PLATE AND CONFINED WHOLLY WITHIN THE WIDER U-SHAPED OPENING IN THE BODY, AND A SECOND PAIR OF "NO GO" THREAD GAGING ROLLS MOUNTED ON SAID PLATE AT OPPOSITE SIDES OF THE U-SHAPED OPENING IN THE PLATE BETWEEN THE FIRST PAIR OF GO THREAD GAGE ROLLS AND THE INNER END OF THE U-SHAPED OPENING IN THE PLATE, AND CONFINED WHOLLY WITHIN THE WIDER U-SHAPED OPENING IN THE BODY. 